EXERCISE TOLERANCE TEST

WHAT YOU CAN EXPECT DURING A REGULAR TREADMILL STRESS TEST?

The patient is brought to the stress laboratory where the heart rate and blood pressure are recorded at rest. Sticky electrodes are attached to the chest and connected to the EKG portion of the stress test machine. A 10-lead EKG is recorded on paper. Each lead of the EKG represents a different portion of the heart, with adjacent leads representing a single wall. The EKG leads are constantly displayed on the treadmill monitor throughout the test. Each lead represents a different section of the heart.

The treadmill is then started at a relatively slow “warm-up” speed. The treadmills speed and its slope/inclination are increased every three minutes according to a preprogrammed protocol. Each three minute interval is known as a Stage (Stage 1, Stage 2, Stage 3, etc. Thus a patient completing Stage 3 has exercised for 3 x 3 = 9 minutes). The patient’s blood pressure is usually recorded during the second minute of each Stage. However, it may be recorded more frequently if the readings are too high or too low.

As noted earlier, the EKG is constantly displayed on the monitor. It is also recorded on paper at one minute intervals. The physician pays particular attention to the heart rate, blood pressure, changes in the EKG pattern, irregular heart rhythm, and the patient’s appearance and symptoms. The treadmill is stopped when the patient achieves a target heart rate (this is 85% of the maximal heart rate predicted for the patient’s age). However, if the patient is doing extremely well at peak exercise, the treadmill test may be continued further. The test may be stopped prior to achievement of the target heart rate if the patient develops significant chest discomfort, shortness of breath, dizziness, unsteady gait, etc., or for EKG changes. It may also be stopped if the blood pressure (BP) rises or falls beyond acceptable limits.